Needle-thread controller for sewing machines



Oct. 15, 1929. J. c. muss 1,732,206

NEEDLE-TERM) CONTROLLER FOR SEWING MACHINES Filed April 16. 192'! III I Witness 6 V m w t fi I i I M 61mm,

Patented Oct. 15, 1929 UNITED STATES PATENT OFFICE JOHN RINGE, OF STBATFORD, CONNECTICUT, ASSIGNOR TO THE SINGER MANUFAC- TUBING COML'ANY, OF ELIZABETH, NEW JERSEY, A CORPORATION OF NEW JERSEY NEEDLE-THREAD CONTROLLER roa SEWING mncnmns Application filed April 16,

and has for its primary object to increase the efficiency of rotary take-ups for the needlethreads of sewing machines operable at high speeds.

In a lock-stitch sewing machine of the rotary hook type, there are two stages in the handling of the needle-thread during the-formation' of each stitch that are particularly critical in the successful operation of the ma chine. In one of these stages, the eye of the descending needle is about to enter the work, at'which point the take-up should begin to provide slack inv the needle-thread, and the other stage occurs as the needle-thread loop is being spread in its passage about the lower thread-case, at which time the beginning of the take-up action to draw up the loop should be delayed sufliciently to provide the slack necessary to permit the loop to reach the hook cast-ofl position.

By reason of itsuniform speed and continuous motion, a take-up of the rotary type lends itself particularlywell to high speed sewing machines, but a simple rotary takeup is limited in its thread-handling capacity in that when the take-up pin is positioned to correctly handle the thread at one of the critical stages referred to, it is improperly timed for the other stage. The importance of these critical stages is increased by the employment of a lower thread bobbin-case having a relatively large thread capacityand also by higher speeds of operation of the machine. Various attempts have heretofore been made to overcome the limitations of a simple rotary take-up and usually by the addition of auxiliary mechanisms having eccentric or oscillatory'motions which complicated'the construction and materially reduced the speed capacity of the machine.

In accordance with the present invention, the problem has been solved in a simple manner by providing a vertically elongated thread-guiding aperture at the lead-in side of the take-up, permitting the thread to freely slide from one end of the aperture to the other and thereby substantially changing the level of the thread lead from the thread- 1927. Serial No. 184,240.

guide to the take-up pin at each of the critical stages noted. As the changes in the levels of the thread leads are to ap roach the general direction of movement 0 the takeup pm at said stages, the take-up begins to give up slack thread at the proper point in 1ts orbit to accommodate the position of the descending needle without sacrificing the subsequent position of the take-up pin for beginning its action to draw up the needlethread loop.

Fig. 1 is a front end elevation of the bracket-arm head of a sewing machine containing the present improvement, the clothplate being shown in section to illustrate the loop-taker and feeding mechanism. Fig. 2 is a front side elevation of the bracket-arm head of the machine, showing. the clothpresser partly in section and a fragmentary view of the cloth-plate.

-Referring to the drawings, the machine frame includes the usual bed or cloth-plate 1, overhanging which is the bracket-arm 2, terminating in the head 3. Mounted for vertical reciprocation in the head 3 is the needlebar 4, carrying the needle 5, complemental to which in the formation of lock-stitches, is

the loop-taker 6, journaled beneath the clothplate 1 for rotation about a horizontal axis and adapted to cast a loop of needle-thread about a thread-mass contained within a bobbin-case 7. The loop-taker illustrated in Fig. 1 of the drawings is of the type makin three revolutions to each reciprocation o the needle, while the bobbin-case 7 is of a size containing a comparatively large mass of under thread, in the present instanceabout 150 yards of #90 cotton-thread. The feeding mechanism shown is of the usual lower four-motion class comprising a feeddog 8 carried by a feed-bar 9, receiving feedadvance movements from a crank-arm 10 of a feed rock-shaft 11, and feed-lift movements from a crank-arm 12 of a feed-lift rockshaft 13. Opposed to the feed-dog 8 is a presser foot 14 carried by a resser-bar 15' suitably journaled for vertical movements in the head 3.

Projecting from the end of the bracket arm head .3 is a circular guide-flange 16 housing the usual rotary take-up disks 17 18 held in spaced relation by the take-up pin 19 and slack-thread controlling pin 20. The disks 17, 18 rotate about a fixed horizontal axis in a continuous direction indicated by the arrow in Fig. 1 of the drawings, any

suitable or well known mechanism being employed for rotating the disks. As illustrated more particularly in Fig. 2, the guardflange 16 is partially cut away at'the front side of the machine head to provide for di-.

' ture adjacent the cut away portion of the guard-flange 16 and thence between thetakeup disks in a direction substantially at right angles to the direction of lead of the thread from the spring 23. As in the present im provement, the thread was led over the takeup pin or member 19 substantially in the plane of rotation of said pin and downwardly through a guide-loop 24 on the head 3 and thence to the needle 5. As the thread is passed over the take-up pin 19 between the disks 17 and 18, the take-up pin necessarily underlies the thread throughout the complete revolution of said pin.

In accordance with the present invention, there is provided an elongated, vertically directed thread-guiding aperture 25 formed in an angular guide-bracket 26, in the present instance secured by screws, as 27 upon the front side of the bracket-arm head 3. The guide-slot 25 is positioned above the horizontal plane containing the axis of rotation of the take-up and is preferably located in a portion of the bracket 26 which is substantially transverse to the general direction of lead of the thread from the spring 23. Furthermore, the guide-slot 25 is positioned closely adjacent the orbit of the take-up pin 19 in order to direct the thread between the disks 17 and18 to said take-up pin in a direction at a substantial angle to the direction of its lead from the spring 23. As the guideslot 25 is located at the front side of the machine and as the take-up pin 19 rotates in a clockwise direction viewed from the front end of the machine, illustrated by the arrow in Fig. 1 of the drawings, it is evident that the effective action of the take-up pin to draw up'the needle-thread loop occurs mainly during that portion of its orbit of travel which is remote from the guide-slot 25.

' In the operation of the machine, the thread drops toward the lower end of the guide-slot 25 during the lower portion of the path of movement of the take-up pin 19 and rises toward the upper end of said slot as the take-up pin rises in its needle-loop drawing up movement and accordingly the needle-thread traverses the elongated aperture 25 in the general direction of movement of the take-up. pin as the latter approaches its final stage of needle-loop drawing up movement. Therei 1 of the drawings, the take-up pin 19 is approximately at the lowest point in its orbit of travel as said take-up pin engages the thread tto begin drawing up of the needle-loop about to be cast off by the'loop-taker, the dotted line position of the pin 1.9 indicating a proxi m'ately the point of completion of t e loop drawing-up movement of said pin in advance of the extreme upper position'reached by the pin in its orbit of travel. By reason of the. described change in the lead of the thread during each revolution of the take-up, the slack-giving time of the take-up pinis accelerated without changing the selected timing of the take-up pin provided for in the design of the parts to the end that the take-up pm will begin its loop drawing-up movement at the proper time. As the slot 25, or referably the major portion thereof, is dlsposed above the level of the take-up axis, the takeup pin'starts to give up slack thread before the needle-eye enters the work.

The accomplishment of this result by the device described permits a machine having a large lower thread mass to be operated at a higher speed than was possible with the com ensators heretofore employed.

aving thus set forth the nature of the invention, what I claim herein is 3 1. In a needle-thread handling mechanism for lock-stitch sewing machines, a rotary take-up for the needle-thread including a take-up pin rotatable in a continuous direction, and a thread-guide disposed closely adjacent the orbit of the take-up pin directing the needle-thread to said take-up pin at substantially different levels at the beginning and ending respectively of each loop drawing-up movement of the take-up pin, the direction of rotation of said take-up pin with respect to the thread-guide being such that its effective action to draw up the needlethread loop is mainly in that portion of its orbit of travel'remote from the thread guide.

2. In a needle-thread handling mechanism for lock-stitch sewing machines, a rotary take-up for the needle-thread including a take-up pin rotatable in'a continuous direc ios tion, and a fixed thread-guide having its thread-receiving and delivery directions at a substantial angle with respect to each other, said thread-guide directing the needle-thread to the take-up pin substantially in the plane of rotation. of said pin at substantially different levels at the beginning and ending respectively of each loop-draWing-up movement of said take-up pin.

3. In a needle-thread handling mechanism for lock-stitch sewing machines, a rotary take-up for the needle-thread including a take-up pin rotatable in a continuous direction about a fixed horizontal axis, and a thread-guide so disposed at the lead-in side of said take-up that the take-up pin begins to draw up the needle-thread loop at approximately the lowest point of the take-up pin and completes its loop drawing-up movement at a point in advance of the extreme upperposition of said take-up pin, said thread-guide directing the thread to the takeup pin in the plane of rotation of said pin at substantially different levels at thebeginning and ending respectively of each loop-drawing-up movement of said take-up pin.

4. In a needle-thread handling mechanism for lock-stitch sewing machines, a rotary take-up for the needle-thread including a take-up pin rotatable continuously about a fixed axis, and a fixed thread-guide-at the side of and closely adjacent to the orbit of said take-up pin, said thread-guide having a substantiall vertically disposed threadguiding slot directing the thread at substantially different levels at the beginning and ending of the action of the take-up pin to draw u up pin aving its effective action to draw up the needle-thread loop mainly in that portion of its orbit of travel remote from the threadguide.

5. In a needle-thread handling mechanism for lock-stitch sewing machines, a rotary take-up for the needle-thread including a take-up pin rotatable about a fixed horizontal axis, and a fixed thread-guide disposed at the side of and closely adjacent to the orbit of,

said take-up pin having an elongated substantially vertically disposedithread-guiding slot directing the thread to the take-up in the plane of rotation of said pin and at substantially different levels corresponding with different positions of the take-up pin, said slot being disposed above the horizontal plane containing the axis of movement of the take up pin.

6. In a lock-stitch sewing machine having a reciprocatory needle, and a rotary looptaker for casting needle-thread loops about a mass of under thread in the formation of lock-stitches,of needle-thread handling mechanism including a take-up pin rotatable about a fixed horizontal axis, and a fixed threadguide positioned closely adjacent the orbit of the needle-thread loop, said taketake-up for the needle-thread including a take-up pin rotating continuously about a fixed axis, and a fixed thread-guide outside of and closely adjacent to the orbit of said take-up pin, said thread-guide having an elongated thread-guiding aperture traversed by the thread in the general direction of movement of the take-u pin as it approaches its final stage of nee le-loop drawing up movement to thereby accelerate the slack giving time of the take-up, and said take-up pin having its effective action to draw u the needle-thread loop mainly in that portion of its orbit of travel remote from the thread-guide.

In testimony whereof, I have signed my name to this specification,

JOHN O. RINGE.

for lock-stitch sewing machines, a rotary 

